1. Field of Endeavor
The present disclosure relates to a surgical blade assembly and to a surgical cutting system. The present disclosure relates in particular to a surgical saw blade assembly for use with a powered surgical driver and to a surgical cutting tool for cutting bones or other tissues.
2. Brief Description of the Related Art
Powered surgical saws are powered tools that surgeons employ for performing certain surgical procedures that include cutting bones and/or other tissues. A powered surgical saw typically includes a handpiece, or driver, in which is housed a motor, for example an electrically or pneumatically driven motor. The motor is attached, for example through a drive shaft, to a head of the driver, which is adapted to removably receive a surgical saw blade. The actuation of the motor causes an oscillating movement of the head and of the attached saw blade. The movement of the saw blade is what gives the blade the power to cut through the tissue it is employed to separate. Powered surgical saws are able to cut through both hard and soft tissue much faster and with greater accuracy than manually operated saws. Powered surgical saws are furthermore able to perform specific cuts that manually operated saws are unable to perform. Also, the physical effort a surgeon has to employ to operate a powered surgical saw is much less than that used when cutting tissue with a manual saw.
Surgical saw blades for use with a powered surgical saw typically have a body with a proximal end, also referred to as the base, that is designed to sit in a slot or opening formed in the driver's head, and a distal end with a cutting portion. The base, or proximal end, is designed to tightly fit in the driver's head in all degrees of freedom in order to remain stable despite the vibrations and pressure it is submitted to when used. The cutting portion usually includes teeth adapted to a particular cutting action. The teeth are usually either fluted or bent, depending on the thickness of the blade and its intended use. The body of the blade is preferably rigid enough for providing a stable and stiff connection between the blade's cutting portion and the driver's head, thereby allowing an accurate cutting action. The length of the body furthermore determines the stroke of the cut, since the amplitude of the driver head's oscillations is constant, independently of the blade being used.
On some drivers, the blade is, for example, attached to the head with the help of bolts and nuts, or other similar locking devices, that hold two coupling members of the head together, between which the surgical saw blade is clamped. Such locking mechanisms can be configured to allow the use of saw blades of different thicknesses on a same head. A drawback of such locking mechanisms, however, is that they require the use of a tool, typically of a wrench, for locking the bolts and/or nuts and thus for securely attaching the blade to the driver's head. This makes replacing saw blades, which often occurs during surgery, a relatively complicated and long task. A further drawback for such a tool is the need to manipulate the head in order to lock the blade in place that may be time consuming and tough to do while using protective gloves.
Other powered surgical saws have heads with tool-less locking mechanisms for coupling the saw blades to the drivers. These mechanisms often require the depression of a button, the rotation or a lever, or some sort of spring loaded device for holding the head coupling members in position so that they lock the saw blade in place. The saw's proximal end for example includes one or more openings or slots in which one or more coupling members integral with the head seat in order to lock the blade to the head. The coupling member is displaced from the locked state to the release state, for example, by the depression of a button also built into the saw head. All one has to do is depress the button in order to move the coupling member to the unlocked state; the surgical personnel then remove one blade and insert a new blade. An advantage of these assemblies is that they eliminate the need to bring another tool, either a small wrench or a key, into the surgical suite. The elimination of this tool eliminates the need to have to sterilize it before an operation and the need to have to account for its presence.
U.S. Pat. No. 5,263,972, for example, describes a surgical powered saw with a tool-less locking mechanism for removably attaching a surgical saw blade to the saw head. The saw described in this document is able to receive blades of a range of thicknesses, wherein the blade's base or proximal end is chucked in a slot whose height can be significantly larger than the blade's thickness. When locked on the saw head, the blade is urged against the top of the slot by spring elements pushing on the blade's lower side. A drawback of this powered saw blade is that if the moment of the forces exerted on the blade's distal end during cutting operations is higher than the moment of the forces exerted on the blade by the spring elements, the saw blade will move in a plane perpendicular to the orientation of its cutting portion, which would greatly impair the accuracy of the cutting operation.